Simulation Tool for Turbomachinery Operating with Trans-Critical Real Fluids

The SCO2 Brayton cycle is gaining interest across a variety of power generation applications due to its potential for providing higher efficiencies. These applications require compressors that operate near the critical point of CO2. However, compressor design at these conditions presents many challenges due to the lack simulation tools that account for the correct fluid property variations in this regime. Our proposed work here addresses this deficiency. A high-fidelity CFD based analysis tool for supporting design and analysis of SCO2 compressors is being developed that will accurately account for the real fluid property variations of CO2 near its critical point. It will provide accurate compressor performance predictions at design and off-design conditions. It will also permit simulations of scaling studies from sub-scale to full-power configurations. In the Phase I effort, a feasibility study of various features necessary for modeling SCO2 compressors was conducted. This included preliminary performance validation, literature survey of thermodynamic properties for CO2 with contaminants, and fundamental condensation studies. The Phase II effort will build upon the feasibility demonstrated in the Phase I effort and mature the simulation framework. Objectives of the work plan include detailed validation of SCO2 compressor performance, thermodynamic models for CO2 with contaminants, and droplet condensation effects on compressor flow fields. The resulting product will be a well-validated design support tool for SCO2 compressors. The SCO2 Brayton cycle is gaining interest across a variety of power generation applications due to its potential for providing higher efficiencies than a steam Rankine cycle. Our proposed work here would provide a high-fidelity design tool that would permit faster development of optimal compressor designs as well as risk mitigation evaluations as these systems are scaled to full power levels.